In order to provide evidence for clinical application, the therapeutic effect and mechanism of Huangqi Bazhen decoction on chemotherapeutic intestinal mucositis induced by capecitabine in mice are investigated. In this paper, the mice are divided into different groups and given capecitabine intragastric administration or treatment drugs. Morphological features of intestinal injury, including villus height shortening, crypt destruction, and apoptosis, are reversed. The experimental results show that Huangqi Bazhen decoction can significantly reduce weight loss and diarrhea during capecitabine treatment. It is also found that GSH-Px and T-SOD can be improved while MDA, IL-1β, and TNF-α are reduced significantly.